In one arrangement, state machines employ a memory array driving a register. The memory array is programmed to contain machine states including a next machine state given a current machine state; and, the register is configured to hold the current machine state. Although, nonvolatile-type memory arrays are most commonly employed, volatile, static, random access memory (RAM) arrays are employed in some applications in which the contents of the memory array may need to be changed. However, to permit the contents of a RAM array to be changed has required that a relatively large number of array addressing lines and a relatively large number of array data (input) lines be connected to associated re-programming circuitry.
To simplify the inter connection of a state machine RAM array with associated re-programming circuitry, Advanced Micro Devices, Incorporated has developed a registered static RAM device which they designate Am9151. In addition to a static RAM array and a pipeline register, the Am9151 device employs a initialize register and a serially loaded serial diagnostic register. Unfortunately, however, to permit the contents of the RAM array of the Am9151 device to be changed still requires that the relatively large number of array addressing lines be connected to the associated re-programming circuitry.